Automatic and remote humidity control



March 13, 1928. 1,662,283

F. W. RUBIN ET AL AUTOMATIC AND REMOTE HUMIDITY CONTROL Filed Oct. 30.1922 2 Sheets-Sheet].

POWER SUP/2) INVENTORS. Flea-05mm w Eva/M By A7758) 5 RUB/A.

ATTORNEYS. I

March 13, 1928.

- 1,662,283 F. w. RUBIN ET Al,

AUTOMATIC AND REMOTE HUMIDITY common Filed Oct. 50. 1922 2 Sheets-Sheet2 INVENT0R5.

FEEDER/(K V14 RUB/N BY HHEEr 5 Bus/A.

A TTORNEYS.

Patented Mar. 13, 1928.

UNITED STATES PATENT OFFICE.

FREDERICK W. RUBIN AND HARRY E. RUBIN, OF INDIANAPOLIS, INDIANA; SAIDHARRY E. RUBIN ASSIGNOR T SAID FREDERICK W. RUBIN.

AUTOMATIC AND REMOTE HUMIDITY CONTROL.

Application filed October 30, 1922. Serial No. 597,909.

The object of this invention is to automatically and remotely controlthe temperature and relative humidity of lumber dry kilns or otherbuildings, rooms, compartments or tanks.

Heretofore in the art of lumber drying, the control devices have beenexposedly positioned within the kiln, the operator manually regulatingthe temperature and humidity after entering the kiln and observing theindicating instruments. Such manual control was not only diflicult butinaccurate wherefore, it is the object of this invention toautomatically control the relative humidity by maintaining the samebetween certain limits which may be fixed by the operator at aconvenient placeand so associated with the recording device as to leavea-record of the operation.

One feature of the invention resides in the use of a dry and wetrecording thermometer apparatus with independent dry and wet extensiontubes remotely positioned in the dry kiln, building, or compartment,said apparatus electrically controlling the heat supply meansindependently of the humidity line, as will be hereinafter more fullyset forth and described.

The invention further contemplates the method of dry kiln operation, andthe mmhanism for controlling the same, which consists in repeatedly andalternately lowering and raising the relative humidity between certainlimits so that when the instrument is once set the process will continuewithout requiring manual attendance and control, a record being made ofthe variation and the temperature control as well as the humiditycontrol.

The full nature of the invention will be understood from theaccompanying drawings and the following description and claims:

In the drawings Fig. 1 is a diagrammatic illustration of the inventionapplied to the outside wall of a compartment or dry kiln. Fig. 2 is anenlarged view of parts of the recording thermometer and controllinginstrument. Fig. 3 is a section taken on line 3--3 of Fig. 2. Fig. 4 isa diagrammatic illustration of an instrument showing a modified formhaving the recording device provided with both temperature and humiditycontrol means. Fig. 5 is a top plan View of a compartment wall, showingthe thermometer tubes positioned within a compartment and the recordingand controlling instruments positioned on the outside thereof. Fig. 6 isa perspective view showing a part of the control mechanism such isillustrated in Figs. 1 to 3 inclusive. Fig. 7 is a sectional View of aportion of the control mechanism as employed in the modified structureillustrated in Fig. 4.

In the wood drying art it is essential that the wood be dried undercertain moisture conditions below which the dryness of the dryingchamber seriously affects the surface of the wood in a manner known inthe trade as case hardening. drying, it must be borne in mind that theheat is the drying force while the moisture is the protective means forguarding against case hardening and the consequent splitting or checkingof the lumber. The method employed in this invention utilizes the dryingmeans or heat in connection with the softening or decasing means such assteam or moisture through a suitable controlling mechanism.

As shown herein, there is a wall 10 of a dry kiln or other compartmentin which it is desired to automatically regulate the heat and moistureor relative humidity. On the outside of the wall there are secured twocontrol devices, a recording dry thermometer 11 and a recording wetthermometer 12. From the thermometer 11, the tube 13 extends in thechamber or compartment and terminates in a temperature susceptible drybulb 113, and from the thermometer 12 another tube Ll extends into thecompartment terminating in a wet. bulb 1114..

The dry recording thermometer is provided with an arcuate bar 16,extending from the center of the instrument 11. to the circumferencethereof and provided with certain graduations or numerals reading fromend to end as from the center to the circumference. This arcuate bar hasits center of curvature at the pivotal mounting of an arm 17 which isinfluenced and moved about In order to control wood its pivotal mountingby the expansion and contraction of a fluid in the tube 13 caused by thechanges in temperature of the compartment. The detail mechanism wherebythe expansion and contraction of the fluid in the tube 13 is transmittedto the arm 17, is illustrated in Fig. 6. It will be later described indetail.

The wet recording thermometer 12 is provided with a similar arm 117. Thearm 17 as well as arm 117, is provided with a recording pen 17 (Fig. 3)which is adapted to form a permanent record upon a recording sheet orchart 17 carried upon the face of the instruments 11 and 12. The bars 16and 116 (as shown in Figs. 2 and 3) are made of a noncondueting materialprovided with a metal wire or bar 21 extending longitudinally throughoutthe face thereof. On each of said bars there is slidably mounted acontact member 22 which is also formed of metal and remains inelectrical contact with the metal bar 21 at all times,

and is held in adjusted position by a setscrew 23. The arcuate length ofcontact 22, as shown herein, is about 15. The arms 17 and 117 aremetallic and are of such length as to extend to a point adjacent theinner surface of the contact 22 so as to engage in contact therewiththrough the medium of the resilient fingers l7 and 117. Thus, upon thearm 17 or 117 being moved by a variation in temperature or humidity to aposition where the fingers 17 or 117 engage the contact 22, the circuitwill be closed therethrough during such time as the respective arms movethrough an arc of substantially 15 to a point where the contact isdisengaged by the finger whereupon the circuit will be broken.

The particular control mechanism for the compartment comprises the heatline 42 and moisture line 41, the heat line 42 is adapted to heat thecompartment by steam passing through a closed coil or circulatory systemwhile the moisture line 41 is adapted to discharge saturated steam intothe compartment. The heat or dry steam line 42 is controlled by valve 43which is maintained in normally closed position by a spring 143, butwhich may be opened against the tension of said spring by a solenoid 44.The moisture or wet steam line 41 is likewise controlled by the valve40, which is normally maintained in closed position by a spring 140 andwhich is opened by the solenoid 38 against the tension of said spring.The valves 40 and 43 are accordingly closed through the action of theirrespective springs. upon their relative solenoids being deenergized buton energizing of their respective solenoids they are open.

The solenoids 38 and 44 are independently controlled by a relay switchas will be further described. The main power lines noid 34. The otherterminal of the soleare connected to said solenoids as follows: A line39 connects one terminal of the solenoid 38 with the line of the powersupply. The other line of the power supply is con nected by the wire 36to the movable element 37 of a normally open switch. The stationarycontact of said switch is connected by a line 136 with the otherterminal of the solenoid 38, the spring 137 normally maintaining theswitch element 37 in open position. Thus the valve 40 is in closedposition as shown in F i 1 through the action of the spring 140 wien theswitch element 37 is held out of contact with the connection 136. Butupon the solenoid 35 being energized and the tension of the sprin 137overcome thereby, the circuit will be c osed through the solenoid 38 andthe valve 40 will be opened to permit wet steam or moistnre to enter thekiln.

The solenoid 44 and, therefore, the valve 43 are somewhat similarlycontrolled. Herein a movable'switch member 237 is normally maintained inclosed position by the spring 337. The solenoid 34 is adapted, uponbeing energized to attract the member 237 and open the circuit inopposition to the spring 337. The normally closed switch member 237 isconnected by the line 46 to one terminal of the solenoid 44, while theother 9 terminal of the solenoid 44 is connected by the line 45 with oneline of the main power supply. The contact made by the switch member 237enclosing the circuit, is connected by the line 145 with the other line1 of the main power supply.

Thus, when the relay or solenoid 34 is energized, the normally closedswitch 237 is opened and the current is out off from the solenoid 44 soas to cause the heat control valve 43 to be closed by the spring 143.'Whenever the solenoid 34 is deenergized the switch 237 will close thecircuit, thereby energizing the solenoid 44 and opening the yallve forallowing dry steam to enter the The wiring connections between thetemperature and humidity thermometers and the solenoids are as follows:The line 20 connects the outer end of the bars 16 and 116 and anextension 31 thereof connects with one terminal of the battery 30. Theother terminal of the battery 30 is connected by the line 130 to oneterminal of the solenoid 34 is connected by the line 32 to the arm 17.The line 32 is provided with a resistance R, and is also connected bythe bran-h 132 to one terminal of the solenoid 35. Said resistance R isslightly greater than the total resistance of the line 33 and solenoid35. The purpose of this resistance is to insure the solenoid 35receiving current when the arm 17 engages the contact 22. Therefore,when both arms are in contact it is immaterial which way the current issupplied to the solenoid '34. The other terminal of the solenoid 35 isconnected by the line 33 to the arm 117.

Reference may now be had to Fig. 6 wherein the interior mechanism forcontrolling the arm 17 by means of the extension tube is illustrated indetail. To the extension tube, in this instance, the tube 13, there isconnected a curved tube 101. Expansion of the heat susceptible fluid intube 13 tends to deform the curved tubular portion 101 and suchdeformation is transmitted through the coil spring 102 suitablysupported in the frame 100. i A shaft 104 is also supported in saidframe 100 and pivotally mounted on said shaft is the arm 17. One end ofthe arm 17 is connected to an angular extension 103 and the coil springmember 102. Suitable means, such as the adjusting screw 105, adjustablyconnects said arm and said extension together so that deformation of theextension tube 101 would be transmitted to the arm 17. The samemechanism is likewise employed for controlling the arm 117.

In Fig. 4 there is shown a modified form wherein both temperature andhumidity arms are combined in a unitary structure, or in other words,both the humidity and temperature thermometers as shown separately inFig. 1 are combined into one instrument as shown in Fig. 4. In thisform, there are provided two arms, one aim being indicated by 217 andcorresponding to the arm 17 above mentioned for indicatingthetemperature and the other arm indicated by 317, being that indicatedin Fig. 1 as 117 for indicating the humidity. Said arms are pivotallymounted upon the same axis 51, one above the other so as to moveindependently of each other. To this structure there is added an arcuatebar 216 corresponding to the bars 16 and 116 above mentioned, upon whichthere are adjustably positioned the contact members 52 and 53 adapted tobe engaged by the arms 217 and 317 respec tively. Connected with each ofthe arms 217 and 317 there are" independent exten sion tubes whichextend into the dry kiln or compartment. The extension tube 213 isconnected with the arm 217 and the tube 214 with the arm 317. Thetubes213 and 214 are provided at their inner ends with temperaturesusceptible bulbs such as 113 and 114 shown in Fig. '5.

In Fig. 7 there is illustrated the mechanism for operating theassociated arms 217 and 317 as shown in Fig. 4, said arms beingpivotally supported at 51 and connected with a coil spring substantiallysimilar to that disclosed in Fig. 6. Thus, each of the coil members 102in Fig. 7 is associated with an indicating arm as shown.

The wiring diagram employed in connection with the construction shown inFig. 4 is substantially the same as illustrated in Fig. 1, the onlychange being that the line 33 is replaced b the line 133, the line 32 bythe line 132 an the line 31 by the line 131. In this construction theline 20 is omitted, since the same is unnecessary. It will further benoted that the line 132 is connected directly with the arm 217 and theline 133 directly with the arm 317, which are insulated from each otheron their pivotal mounting 51.

The operation of the device is as follows, reference being had toFig. 1. After the green wood is placed in the kihi, the contacts 22 uponthe bars 16 and 116 are adjusted to the desired positions, and thecontact finger 117, on the arm 117, is set to engage the contact 22 onthe bar 116. 'When the main switch (not shown) in the main power line isclosed the circuits are energized as follows: Since the finger 117 is inengagement with the contact 22, both solenoids 34 and 35 will beenergized, thereby closing the circuit through the switch 37, to supplyenergy to the solenoid 38 to open the valve 40 and supply wet steam tothe compartment. At the same time the solenoid 34 is energized to openthe circuit through switch 237, and thereby open the circuit through thesolenoid 44. This deenergizes the same and permits the spring 143 toclose the valve 43 in the dry steam line. The valves are thus alternately and oppositely or differentially operable. As the temperature isincreased in the compartment or kiln, due to the heat in the wet steam,both arms 17 and 117 tend to travel from the center toward the peripheryof the thermometer.

When arm 117 passes beyond contact 22 on bar 116 the wet steam is out01f. If arm 17 is not on contact 22 of bar 16 when this occurs the heatlineimmediately is opened. If arm 17 is on its contact the heat line ismaintained closed until such time as the compartment cools. "While suchcooling occurs both arms reverse their travel with the fall intemperature therein and upon the finger 117 engaging the contact 22 ofthe wet ther mometer in its return travel, the wet steam will again beintroduced into the compartment and the operation repeated. If therelative humidity is such that both fingers pass out of engagement withtheir contacts 22, the respective valve controlling circuits will beopened through the solenoids 34 and 35 and thereby permit the dry steamvalve to be opened and the wet steam valve to be closed so as to supplydry steam to the compartment for heating purposes only. As the dry steamincreases the temperature in the compartment, the humidity decreases andcauses a cooling, due to evaporation of the wet bulb thermometer,thereby causing the wet bulb thermometer to trail the dry thermometerbut nevertheless rising therewith, showing that the change in humidityis expressed as a temperature change. When the finger 117 again engagesthe contact 22 of the wet bulb thermometer, such engagement serves tocut off the dry steam and again supply wet steam to the kiln. Wheneverthe positions are such that both fingers pass the contacts 22, the drysteam line 42 will be open, thereby increasing the temperature. Suchincreased temperature will cause the wet bulb thermometer to trail dueto evaporation, until the contact 117* engages the contact 22 and againcuts out the dry steam line and energizes the wet steam line, therebypositively protecting the wood in the compartment against drying in ahumidity which is exceedingly dangerous.

After the drying progresses, the duration of the cycle graduallydecreases since the amount of moisture derived from the wood isgradually becoming less. The heating period betwcen= successivesaturating intervals will remain relatively constant. This is because ofthe decrease in loss of temperature by evaporation. The saturatinginterval between successive heating intervals gradually decreases afterthe drying is continued, so that toward the end of the drying period forwhich the temperature and relative humidity conditions have beenadjusted, the interval of saturation grad-' ually approaches theinterval of heating so that both sides of the curve for the completecycle approach each other, whereas the initial cycle or cycles in anygiven point show a relatively steep drying interval and a relativelylong and sloping saturating interval. Likewise the total interval foreach cycle gradnially decreases during any given After this cyclicalperformance has been repeated for the desired total interval, thecontacts upon the wetand dry bulb thermometers may be manuallyreadjusted for the subsequent drying period. These new limits and theintervals may be substantially those well known in the art, and whichheretofore have been manually maintained.

.The present invention maintains the desired limiting factors andprevents drying of the wood under adverse conditions.

From the foregoing, therefore, it will be understood that the drying isalways accomplished in cycles and that after operation has been startedand the contacts have been adjusted, there is an alternate and repeatedraising and lowering of the temperature in the kiln accompaniedsimultaneously, as a rule, by a lowering and raising of the relativehumidity. Thus drying may be accomplished as a forced return byutilizing heretofore considered excessive temperatures but theseexcessive temperatures as will be apparent from the foregoing, areinjurious if the relative humidity is such that the same does not takeplace for any excessive or dangerous interval. The invention disclosedherein assures that excessive temperatures may be utilized because thewood is always protected against excessive or injurious drying. Thelimits are those heretofore usually utilized. The present inventionmechanically controls forced but noninjurious lumber drying, whereby thetotal drying period is materially reduced.

It will be understood that the essential features of the inventionconsist in securing a permanent record of the conditions under whicheach batch of lumber. was dried. Second, the remote control of theconditions within the compartment. Third, the automatic protectivearrangement whereby the wood can not be dried under humidity conditionswhich will damage the wood and of course; the combination of theseseveral eatures remains a most desirable construction for remotelycontrolling and recording the drying of the lumber.

The invention claimed is:

1. In a device for controlling the temperature and relative humidity ina compartment, the combination of dry and wet thermometer apparatusnormally unexposed to the compartment but with independent extensionsexposed therein, electrically operable means controlling the temperatureand relative humidity in the compartment, and indicating means alsonormally unexposed to the compartment including a temperature responsiveindicating arm and a bar cooperating therewith.

2. In a device for controlling the temperature and relative humidity ina compartment, the combination of a unitary wet and dry thermometerapparatus normally unexposed to the compartment but with independentextensions exposed therein, electrically operable means controlling thetemperature and relative humidity in the compartment, and indicatingmeans for each portion of said wet and dry apparatus also normallyunexposed to the compartment including a temperature responsiveindicating arm and a bar co-operating therewith.

.3. In a device for controlling the temperature and relative humidity ina compartment, the combination of dry and wet thermometer apparatusnormally unexposed to the compartment, but with independent extensionsexposed therein, electrically operable means controlling the temperatureand relative humidity in the compartment, and indicating and recordingmeans also normally unexposed to the compartment including a temperatureresponsive indicating and recording arm and a bar co-operatingtherewith.

4. In a device for controlling the temperature and relative humidity ina compartloo compartment including a temperature re sponsive indicatingand recording arm and a bar cooperating therewith.

5. A device for controlling the temperature and relative humidity in drykilns, the

combination of dry and wet thermometer apparatus unexposedly positionedwith respect tothe compartment and having independent extensionsexposedly positioned to terapparatus, a contact adjustably mounted uponsaid bar and means operable by the the relative humidity within saidcompartment, a bar mount-ed adjacent the thermomethermometer apparatusfor engaging and disengaging-the contact for controlling the relativehumidity-within the compartment. 6. In a device for controlling theteInperature and relative humidity in a com- ,partment, the combinationof dry and wet thermometer apparatus, and electrically operable meanscontrolling the temperature and relative humidity in the compartment forrepeatedly and alternately raising and lowering the relative humidity ofthe air in said compartment. 7. In a device for. controlling thetemperature and relative humidity in a compartment, the combination ofdry and wet thermometer apparatus, and means actuated by said dryand.'wet thermometer apparatus forcontrolling the temperature andrelative humidity in the compartment for repeatedly and alternatelylowering and raising the relative humidity of the air in saidcompartment.

8. In a device for controlling the temperature and relative humidity ina compartment, the combination of dry and wet thermometer apparatus,electrically operable means controlling the temperature and relativehumidity in the compartment and indicating means including a temperatureresponsive indicating arm anda bar cooper ating therewith.

9. In a device for controlling the temperature and relative humidity ina compartmometer apparatus, electrically operable means controlling thetemperature and relative humidity in the compartment for repeatedly andalternately raising and lowering the relative humidity of the air insaid' compartment, and means for adjusting the temperature of the airafter the drying continues.

10. In a device for controlling the tempartment, the combination. of'drand wet thermometer apparatus, electrical y operable means controllingthe temperature and relative humidity in the compartment for repeatedlyand alternately raising and lowering the relative humidity of the air insaid compartment, and means for adjusting the relative humidity lowerlimit.

11. In a device for controlling the tem perature and relative humidityin a compartment, the combination of air humidifying means therefor,control means for said air humidifying means, and automatic means foroperating said control means to produce alternate lowerings and raisingsof the relative humidity of the air in said compartment.

In witness whereof, we have hereunto affixed our signatures.

FREDERICK w. RUBIN. HARRY E. RUBIN.

-ment, the combination of dry and wet therperature and relative humidityin a com-

